Examples

Example 1: Keep only search results whose "_raw" field contains IP addresses in the non-routable class A (10.0.0.0/8). This example uses a negative lookbehind assertion at the beginning of the expression.

... | regex _raw="(?<!\d)10\.\d{1,3}\.\d{1,3}\.\d{1,3}(?!\d)"

Example 2: Keep only the results that match a valid email address. For example, buttercup@example.com.

...| regex email="/^([a-z0-9_\.-]+)@([\da-z\.-]+)\.([a-z\.]{2,6})$/"

The following table explains each part of the expression.

Part of the expression

Description

/^

Specifies to start at the beginning of the string.

([a-z0-9_\.-]+)

This is the first group in the expression. Specifies to match one or more lowercase letters, numbers, underscores, dots, or hyphens. The backslash ( \ ) character is used to escape the dot ( . ) character. The dot character is escaped, because a non-escaped dot matches any character. The plus ( + ) sign specifies to match from 1 to unlimited characters in this group. In this example this part of the expression matches buttercup in the email address buttercup@example.com.

@

Matches the at symbol.

([\da-z\.-]+)

This is the second group in the expression. Specifies to match the domain name, which can be one or more lowercase letters, numbers, underscores, dots, or hyphens. This is followed by another escaped dot character. The plus ( + ) sign specifies to match from 1 to unlimited characters in this group. In this example this part of the expression matches example in the email address buttercup@example.com.

([a-z\.]{2,6})

This is the third group. Specifies to match the top-level domain (TLD), which can be 2 to 6 letters or dots. This group matches all types of TLDs, such as .co.uk, .edu, or .asia. In this example it matches .com in the email address buttercup@example.com.

Comments

Nbeuchat and Boopaljothi
Thank you for your question about the Example 1 expression that began with (?=!\d)
This is supposed to be a negative lookbehind assertion.
The correct expression should be (?<!\d).
I have changed the example and added a brief explanation.

Lstewart splunk, Splunker

October 11, 2016

In example 1, I believe the first part of the regex should be (negative lookbehind of a digit)
(?>!\d)
and not
(?=!\d)
The current regex means positive lookahead for an exclamation mark followed by a digit.

Nbeuchat

October 10, 2016

Is there a way to do KVP extraction inl-lined ("(?<_KEY_1>[a-z]+)=(?<_VAL_1>[a-z]+)") like it shows here:
http://docs.splunk.com/Documentation/Splunk/latest/Data/Configureindex-timefieldextraction#Add_a_regex_stanza_for_the_new_field_to_transforms.conf

Woodcock

February 25, 2016

In example 1 what does (?=!\d) this refer to?
In example 2 what does regex(?=expression refer to?
i know that -? refers zero or one dash but what does above statements refer

Boopaljothi

December 23, 2015

Woodcock - Thanks for your comment. The regular expression should be unanchored. I've updated the documentation.

Lstewart splunk, Splunker

December 4, 2015

You should mention whether the PCRE application is anchored or not.

Woodcock

September 21, 2015

how would one search for an expression containing a quote? i.e. How should we escape the quote character?

Chaospixel

May 15, 2014

So you can't pass other regex options like case-insensitive like "/regex/i" (i for case-Insensitive)?

Hobbes3

July 25, 2013

Is the regex in Example 1 wrong? I think the "(?=!\d)" should be "(?&lt;!\d)" and the first full stop (.) should be escaped. Is that correct? (By the way, you might want to look at having "

Shtark

July 7, 2013

Thanks for pointing that out, Daniel333. The "3" was a typo. We've fixed it.

Cgales splunk, Splunker

March 20, 2013

Example 1 and 3. Where is 2?

Daniel333

March 20, 2013

the syntax indicates that regex can be used without specifiying field name, which I dont think is correct<br /><br />Syntax<br /><br />regex = | != | <br /><br />I interperate the above as:<br />args to regex are:<br />field equals regex-expression OR field NOT equal to regex-expression OR regex-expression<br /><br /><br />is the syntax correct? if so why can I not do?:<br />regex <br /><br />I get the following error message:<br />Error in 'SearchOperator:regex': Usage: regex (=|!=)

regex

Enter your email address, and someone from the documentation team will respond to you:

Please provide your comments here. Ask a question or make a suggestion.

Feedback submitted, thanks!

You must be logged into splunk.com in order to post comments.
Log in now.

Please try to keep this discussion focused on the content covered in this documentation topic.
If you have a more general question about Splunk functionality or are experiencing a difficulty with Splunk,
consider posting a question to Splunkbase Answers.